Alberti bass is a particular kind of accompaniment in music, often used in the classical music era. It was first used by Domenico Alberti, after whom it is named.

Alberti bass is a kind of broken chord or arpeggiated accompaniment, where the notes of the chord are presented in the order lowest, highest, middle, highest. This pattern is then repeated. A well known example is found at the beginning of Wolfgang Amadeus Mozart's Piano Sonata, K 545:

Alberti bass is usually found in the left hand of pieces for keyboard instruments. However, it is sometimes found in instrumental pieces, Béla Bartók using it towards the end of his String Quartet No. 5, for example.